Our toy model exposes new features that in principle should allow to discriminate circular fuzz-balls from (small) BHs. As we will see the absence of a horizon, replaced by a smooth cap in the geometry, produces a new set of long-lived QNMs that correspond to meta-stable states trapped in the `potential well' inside the photon-sphere that slowly leak out to infinity by `quantum' tunnelling through the barrierWe put `quantum' in quotes since we actually deal with 'classical' waves!. In binary mergers these long-lived QNMs should appear in the echoes [1]}, [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]} that dominate the late stage of the GW signal and should be `easily' recognisable from the photon-sphere QNMs that dominate the prompt ring-down phase.
